Making Wireless FM microphone as a beginner project is interesting, crystal oscillator can be controlled, with a harmonic change to 2p7-5 crystals. The oscillator will then be very stable, so stable in fact, that he could not even set! This means you can only use it to send CW .One solution to this problem would be to use a low frequency crystal oscillator and modulate it. Because the crystals can be modulated by typically only 1kHz or 2KHz, then the multiplication factor should be around 72. This will require 1.3888MHz crystal and several multiplier stages, each individually adjustable. The first phase will also be set to double if the transmitter is to have a low signal.